The third-generation (3G) mobile communication systems are starting in commercial services worldwide. Though 3G wireless systems can offer higher transmission rate and support certain multimedia services, it has many problems in the closed network architecture, quality-of-service (QoS) guarantee, closed air interface architecture and limited data rates for future multimedia services due to the continuous increase of subscribers and traffics.
Traditionally, all mobile communication services are based on specific wireless radio transmission technologies (RTT) or air interfaces such as GSM (global service for mobile communication) and CDMA (code division multiplexing access) networks. With more and more applications and services are developed for wireless mobile communications, the conventional radio access network architecture based on closed and specific RTTs are not suitable for such future service delivering platform.
The future wireless and mobile communication services require both broadband multimedia transmission in a more spectrum-efficient fashion, and the conventional voice and data services in a more cost-effective fashion. In addition, the wireless broadcast and multicast services for the mobile terminal users are becoming very important and how to improve the transmission performance for such broadcast and multicast services is very critical in terms of spectrum utilization efficiency and QoS requirements.
The main considerations of the future commercial mobile and wireless communication networks should comprise:                1. High spectrum utilization efficiency and dynamic spectrum access capability because the wireless spectrum is a very limited natural resource, and becomes much more and more expensive in the future,        2. Broadband high-speed transmission capability to support the wireless multimedia services,        3. Seamless mobility capability to have users access the information from anywhere, anytime and anyone,        4. Asymmetric and adaptive transmission capability in both uplink and downlink channels to support open service architecture of mobile communications,        5. Cost effective system platform for the commercial applications which means the business model and value chain are targeted for profits as the first consideration,        
Technically, no single wireless RTT or air interface can meet all the above five requirements for the future commercial mobile and wireless communications.
Therefore, the future commercial wireless and mobile communications must be based on a new architecture to converge multiple RTTs or air interfaces onto one common broadband wireless system platform which is technically called “Open Wireless Architecture (OWA)”.
Similar to the personal computer system with Open Computer Architecture (OCA), OWA defines an open convergence platform so that different RTTs, such as OFDMA (orthogonal frequency division multiplexing access), CDMA and TDMA (time division multiplexing access), can work together as a whole to compliment each other in any optimal way to deliver the service-oriented transmission platform, rather than the standard-specific platform. Based on OWA architecture, two or three selected RTTs can fully meet all the five requirements for the future commercial mobile wireless communications.
Based on the OWA convergence platform, different multiple radio access networks can work together and operate as a common system platform in providing the converged networks and services delivering infrastructure, to be integrated with the backbone IP core networks to realize the total convergence across the multi-layered information delivery architecture.
With the OWA convergence framework, the very high-speed broadband wireless transmissions (date rate around 100 Mbps and above) are limited to the high spectrum band above 3 GHz, and the seamless mobile transmission and wide area radio transmission are limited to the low spectrum band of 3 GHz and below. The converged OWA system can support the future mobile and wireless communication services of variable data rates from hundreds of Kbps to hundreds of Mbps in one radio system, by supporting open air interfaces including CDMA, TDMA and OFDMA for the common access networks.
OWA systems are totally different from those of traditional wireless radio communication architecture including software definable radio (SDR) in that the OWA system modules, such as service layer, network layer, link layer, access control layer and physical layer, are extensible, upgradeable, variable and removable for the optimized convergence of access networks and service delivery. OWA wireless platform is optimized for the seamless convergence by mapping various wireless air interfaces (RTTs) into open interface parameters defined by the OWA BIOS (basic input/output system) and Framework architecture.
In addition to the open air interfaces of future wireless transmission, there is an ever-increasing desire to access various types of multimedia content by a ubiquitous and open access network, and the future fourth generation (4G) mobile system will become the backbone of multimedia communications. Traditionally, services and networks are tightly coupled, because different networks have different characteristics and capabilities, and different services can only be supported via specific network. For example, voice in telecommunication networks, and TV in broadcast cable networks. Now, both services and networks are evolving to be more efficient to support IP (Internet Protocol) technology, and this will bring the convergence of services on different networks, and bring the network convergence in the end. So we can say the converged network can be defined as a network with harmonic co-existence between unicast service, broadcast/multicast service and quality service continuity of multiple traffics. Unified service delivery platform (SDP) is necessary to simplify the maintenance and operation, and reduces the expenditure of the operators which is very important for commercial mobile communications.